This invention relates to compositions useful as defoamers for water-based compositions, and to the aqueous compositions containing the defoamers.
In the preparation and use of aqueous paints and other aqueous-based compositions, problems with foaming are frequently present, causing the encapsulation of air bubbles in the aqueous compositions. These air bubbles are especially troublesome in latex paints and in the coatings resulting therefrom.
Consequently, there is a continuing demand for defoaming agents that will successfully defoam aqueous compositions while not interfering with the desirable properties of the aqueous compositions.
This invention relates to defoaming compositions, and to aqueous-based compositions containing them.
The defoaming compositions of the invention comprise
A) at least one organosilicone compound; and
B) at least one reaction product comprising the following reactants:
a) a linking agent of formula I
R4(Y)3xe2x80x83xe2x80x83(I)
wherein each Y group is a halogen atom or one Y group is a halogen atom and two Y groups with two adjacent carbon atoms in the R4 group and an oxygen atom form an epoxy group, and R4 is an alkanetriyl group containing from 3 to 10 carbon atoms, the preferred linking agent being epichlorohydrin; and
b) a compound of formula II
R3(EO)n(PO)m(BO)pXxe2x80x83xe2x80x83(II)
wherein R3 is a substituted or unsubstituted, saturated or unsaturated, organic oxy or thio group having from 1 to 36 carbon atoms or a secondary amino group having from 2 to 36 carbon atoms; n is a number of from 0 to 50, e.g., from 1 to 50; m is a number of from 0 to 50 e.g., from 1 to 50; p is a number of from 0 to 50 e.g., from 1 to 50; and X is hydrogen, or X can be a mercapto group or an amino group in place of a terminal xe2x80x94OH group, provided that when X is mercapto or amino; the sum of n, m, and p must be at least 1.
Other than in the operating examples, or where otherwise indicated, all numbers expressing quantities of ingredients or reaction conditions used herein are to be understood as modified in all instances by the term xe2x80x9caboutxe2x80x9d.
It is to be understood that the terms xe2x80x9cdefoaming compositionsxe2x80x9d, xe2x80x9cdefoaming agentsxe2x80x9d, xe2x80x9cdefoamersxe2x80x9d, and the like as used herein refer to compositions that reduce or eliminate foaming when added to water-based compositions.
In the component B) product of the reaction between the linking agent of formula I and the compound of formula II, the mole ratio of I:II is from 0.2:1 to 5:1, preferably from 0.4:1 to 2:1, and more preferably from 0.6:1 to 1.4:1.
The linking agent of formula I is preferably epichlorohydrin although other epihalohydrins can be used. Also, trihaloalkanes can be used, such as 1,2,3-trichloropropane, 1,2,4-trichlorobutane, 1,3,6-trichlorohexane and the like. Instead of chlorine in the epihalohydrins and the trihaloalkanes, the corresponding bromine and iodine compounds can also be used, including compounds containing two or even three of the above halogens.
In the compounds of formula II, it is understood that EO stands for the residue of ethylene oxide and PO stands for the residue of propylene oxide and BO stands for the residue of butylene oxide.
When the X group of formula (II) is a mercapto group, the R3 group will preferably have from about 4 to about 36 carbon atoms, examples of which include but are not limited to, alkoxylated dodecyl mercaptan and alkoxylated 1-hexadecanethiol.
The compounds of formula (II) can be alkoxylated or non-alkoxylated secondary amines. When the compounds of formula II are secondary amines, n is a number from 0 to 50, preferably from 1 to 50, m is a number from 0 to 50 and p is a number from 0 to 50, preferably from 1 to 50. Examples of the secondary amines useful for the purposes of the invention include but are not limited to, alkoxylated dibutyl amine, alkoxylated dicyclohexyl amine, alkoxylated diethylethanolamine, and alkoxylated dioctylamine.
The substituents that can be present on the substituted R3 groups can be single or multiple substitutions such as a halogen substitution, for example Cl, Fl, I and Br: a sulfur functionality such as a mercaptan or thio group; a nitrogen functionality such as an amine or amide functionality; an alcohol functionality, a silicon functionality, e.g., a siloxane; an ether functionality; or any combination thereof.
In general, compounds of formula II wherein the sum of n, m, and p is at least 1, especially at least 2, are preferred.
When R3 is a secondary amino group, the group preferably contains from 4 to 22 carbon atoms.
Also, when X is hydrogen p is preferably a number of from 1 to 50. When R3 is a secondary amino group, p is preferably a number of from 1 to 50.
The nonoxy and nonthio components of the R3 group can be any substituted or unsubstituted, saturated or unsaturated organic moiety having from 1 to 36 carbon atoms. Thus, the nonthio and the nonoxy components of the R3 aliphatic group can be linear or branched alkyl groups, linear or branched alkenyl or alkynyl groups, saturated carbocyclic moieties, unsaturated carbocyclic moieties having one or more multiple bonds, saturated heterocyclic moieties, unsaturated heterocyclic moieties having one or more multiple bonds, substituted linear or branched alkyl groups, substituted linear or branched alkenyl or alkynyl groups, substituted saturated carbocyclic moieties, substituted unsaturated carbocyclic moieties having one or more multiple bonds, substituted saturated heterocyclic moieties, and substituted unsaturated heterocyclic moieties having one or more multiple bonds. Examples of the above include but are not limited to an alkyl group having from 4 to 22 carbon atoms, an alkenyl group having from 4 to 22 carbon atoms, and an alkynyl group having from 4 to 22 carbon atoms. R3 can also be an arenyl group. Arenyl groups are alkyl-substituted aromatic radicals having a free valence at an alkyl carbon atom such as a benzylic group. Alkyl groups having from 4 to 12 carbon atoms are preferred, and alkyl groups having from 8 to 10 carbon atoms are most preferred. The degree of ethoxylation is preferably from 2 to about 50 with the most preferred being from about 4 to about 50 while the degree of propoxylation and butoxylation can vary from 0 to about 50, preferably from 1 to about 10. The degree of propoxylation and or butoxylation will be determined by the desired degree of solubility or miscibility in the aqueous compositions of the invention. The solubility or miscibility will ultimately be determined by such factors as the number of carbon atoms in R3 and the relative amounts EO, PO and BO.
Optionally, an additional component can be reacted with the linking agent of formula (I) and the compound of formula (II). A glycidyl ether or amine can be added to the reaction of formula (I) and formula (II). The amount of the glycidyl ether or glycidyl amine is from about 1 to about 20 mole percent based on the moles of formula (II) used in the reaction. When the glycidyl ether or glycidyl amine is added to the monofunctional starting material of formula II, the ratio of formula I to formula II plus the glycidyl ether or glycidyl amine is preferably from about 0.8 to about 1.4. Examples of the glycidyl ethers include, but are not limited to, PEG 600 Diglycidyl ether, TETRONIC(trademark) 701 Tetraglycidyl ether, Triglycidyl Di or Triethanolamine, Polyoxyethylene (POE) 200 Tallow amine diglycidyl ether, Propoxylated (POP10) Trimethylol propane triglycidyl ether, Propoxylated (POP7) Pentaerythritol tetraglycidyl ether. Examples of glycidyl amines include, but are not limited to, Tetraglycidyl 1,6-Hexane diamine, JEFFAMINE(trademark) Tetraglycidyl EDR-148, and Tetraglycidyl Isophorone diamine.
The component B) reaction products can be prepared by the process disclosed in U.S. Pat. No. 5,827,453, the disclosure of which is expressly incorporated herein by reference.
With respect to the component A) organosilicone compounds, most of these are organopolysiloxanes, preferably those having defoaming activity in aqueous-based compositions. Examples of the latter compounds are TEGO FOAMEX(copyright) 3062, 810, and 840, which are organo-modified polysiloxanes, manufactured by Tego Corporation of Hopewell, Va.; AF 9000, an organo-modified polyether polysiloxane manufactured by General Electric Co. of Waterford, N.Y.; and DC 2000, an organo-modified polysiloxane manufactured by Dow Corning of Midland, Mich.
The defoaming compositions of the invention can also contain other components, such as polyethylene glycols, surfactants, mineral oils, water, silicas, waxes, and the like.
The proportions of components A) and B) that can be present in the defoaming compositions can range from 90:10 to 10:90 percent by weight, preferably from 80:20 to 50:50.
The defoaming-effective quantities of the present defoaming compositions in aqueous compositions can be readily determined for any particular aqueous composition, and are generally in the range of from 0.01 to 2% by weight, more usually in the range of from 0.025 to 1.5% by weight, based on the weight of the aqueous composition.
The defoaming compositions of the invention are prepared by mixing the components together, which can be done at room temperature or at an elevated temperature, e.g., from 30 to 160xc2x0 C., depending on the particular components selected.
The aqueous compositions to which the defoaming compositions of the invention can be added to include latex paints, inks, adhesives, latex processing, metal working, and the like.
The aqueous compositions of the invention when formulated with the present defoamers have very low levels of air entrapment. When used in latex paint compositions, the paints when cured have almost no surface defects such as orange peel, fish eyes, cratering or pin holing. In addition, not only do the defoamers of the invention provide excellent defoaming action during formulation, but they also act as flow and leveling agents in latex paints, with very low levels of trapped air and high gloss when the coating is applied to a substrate. In some cases, the present defoamers may actually enhance gloss in the dried coatings.
The invention will be illustrated but not limited by the following examples.